basically, to build an update, you need the base pkg. I think they're tied together by something called the digest, which is the ps4 way of saying checksum. it's to guarantee that an update goes with that game. if you dumped the game yourself, along with pkg, you shouldn't have to remarry. however, the base pkg must be the same one used when the update was created. if not, it has to be remarried, which is just decrypting the pkg, then using the base game to recreate the update pkg. even if you dump the same game, same system, the base pkg created must match the update. if it's a different dump, it needs to be remarried.
